OF MERGUI AND ITS ARCHIPELAGO. 



203 



Large specimens 25 centim. broad, 19 millini. high. Edges 

 yellowish, not blackish as in Australian specimens {Reeve, 

 I. c. x. pi. i. fig. 1). 



Elphinstone Island ; Owen Island. Red Sea, Mauritius, 

 Madras, Ceylon, Andamans. 



281. Ayicula atropurpurea, Dunker, Monogr. Avicula in 

 Kuster's Conch -Cab. pi. 3. fig. 3. 



Shell rather square, dark-coloured. 

 Elphinstone Island f. 



282. Ayicula Chemnitzii, Philippi, Zeitschr. f. Malah. Zool. 

 1849, p. 20; Chemnitz, Conch.-Cab. viii. fig. 720; Dunker, 

 Monogr. pi. 3. fig. 5. 



Avicula prsetexta, Reeve, Conch. Icon. x. pi. vii. fig. 15, 

 Shell orbicular, hinder wing very prominent. 

 Elphinstone Island. China Sea. 



283. Ayicula scabriuscula, Reeve, I. c. x. pi. xiv. fig. 54. 

 Obliquely elongated, covered with a net-like fibrous pale-brown 



periostracum, the scale-like prominences of which are compara- 

 tively much longer iu young than in full-grown specimens. 

 King Island ; Elphinstone Island. Australia. 



284. Perna ephippium, L., Chemnitz, vii. fig. 576. (Not Reeve, 

 I. c. xi. pi. ii. fig. 8, which is a species from the West Indies.) 



Mergui ; King Island, on rocks ; Crow Islet between King 

 and Hayes Islands, beneath stones ; Kisseraing Island. Mozam- 

 bique, Mauritius, Nicobars, Singapore, Celebes, Philippines, West 

 Australia. 



285. Perna iso gnomon, L., Chemnitz, vii. figs. 582-584 ; 

 Reeve, Conch. Icon. xi. pi. v. fig. 24. 



The relative length of the arm-like prolongation of the shell is 

 very variable. 



King Island; Elphinstone Island; Owen Island; Sullivan 

 Island, coral bottom ; Lampee. Mozambique, Singapore, Phi- 

 lippines. 



286. Perna spatulata, Reeve, Conch. Icon. xt. pi. vi. fig. 28. 

 Oblong-oval. 



King Island ; Elphinstone Island. Philippines . 



LINN. JOURN. — ZOOLOGY, YOL, XXI. 17 



